nag – Detecting and warning about obsolete LaTeX commands

Old habits die hard. All the same, there are com­mands, classes and
pack­ages which are out­dated and su­per­seded. The nag pack­age
pro­vides rou­tines to warn the user about the use of such ob­so­lete
things. As an ex­am­ple, we pro­vide an ex­ten­sion that de­tects many
of the “sins” de­scribed in
l2tabu.